If the amount of fetal hemoglobin in the red cells of patients with sickle cell anemia or thalassemia major could be increased, their clinical condition would be ameliorated. Administration of 5 azacytidine has produced such changes, and in the one patient with sickle cell anemia we have treated for almost a year, definite clinical and hematological improvement has been observed. The drug can be toxic, and is potentially carcinogenic, limiting its use to severely affected patients. We propose to 1) develop an effective means for oral administration of the drug to the two patients with sickle cell anemia currently being treated; 2) expand the number of such patients to five adults and make observations of clinical and hematologic efficacy over a period of at least a year, using historical controls; and 3) include one or more adult patients with thalassemia major and manifestations of cardiac hemochromatosis. The application primarily seeks support for a research associate and supplies necessary to assay "F cell", the sole technique for assay of drug effect in vitro. 5 azacytidine is an orphan drug because the pharmaceutical company which holds the patent has decided not to develop it for the use described here, but rather, solely as an anti-neoplastic agent.